Diabetes Care Volume 40, August 2017 1065 Frans K. Gorus,1,2 Eric V. Balti,1,2 Twenty-Year Progression Rate to Anissa Messaaoui,3 Simke Demeester,1,2 Annelien Van Dalem,1,2 Olivier Costa,1,2 Clinical Onset According to Harry Dorchy,3 Chantal Mathieu,4 fi Luc Van Gaal,5 Bart Keymeulen,1,6 Autoantibody Pro le, Age, and Daniel¨ G. Pipeleers,1 and Ilse Weets,1,2 for HLA-DQ Genotype in a Registry- the Belgian Diabetes Registry* Based Group of Children and Adults With a First-Degree Relative With Type 1 Diabetes Diabetes Care 2017;40:1065–1072 | https://doi.org/10.2337/dc16-2228 OBJECTIVE We investigated whether islet autoantibody profile, HLA-DQ genotype, and age influenced a 20-year progression to diabetes from first autoantibody positivity (autoAb+)infirst-degree relatives of patients with type 1 diabetes. PATHOPHYSIOLOGY/COMPLICATIONS 1Diabetes Research Center, Vrije Universiteit RESEARCH DESIGN AND METHODS Brussel, Brussels, Belgium Persistently islet autoAb+ siblings and offspring (n =462)under40yearsofagewere 2Department of Clinical Chemistry, Universitair followed by the Belgian Diabetes Registry. AutoAbs against insulin (IAA), GAD Ziekenhuis Brussel, Brussels, Belgium 3Department of Diabetology, Hopitalˆ Universitaire (GADA), IA-2 antigen (IA-2A), and zinc transporter 8 (ZnT8A) were determined by des Enfants Reine Fabiola, Brussels, Belgium radiobinding assay. 4Department of Endocrinology, Universitair Ziekenhuis Leuven, Leuven, Belgium RESULTS 5Department of Endocrinology, Diabetology and The 20-year progression rate of multiple-autoAb+ relatives (n = 194) was higher than Metabolism, Universitair Ziekenhuis Antwerpen, + Antwerp, Belgium that for single-autoAb participants (n = 268) (88% vs. 54%; P < 0.001). Relatives 6Department of Diabetology, Universitair positive for IAA and GADA (n = 54) progressed more slowly than double-autoAb+ Ziekenhuis Brussel, Brussels, Belgium + individuals carrying IA-2A and/or ZnT8A (n = 38; P = 0.001). In multiple-autoAb Corresponding author: Ilse Weets, ilse.weets@ relatives, Cox regression analysis identified the presence of IA-2A or ZnT8A as the uzbrussel.be. only independent predictors of more rapid progression to diabetes (P < 0.001); in Received 17 October 2016 and accepted 22 April single-autoAb+ relatives, it identified younger age (P < 0.001), HLA-DQ2/DQ8 geno- 2017. type (P < 0.001), and IAA (P = 0.028) as independent predictors of seroconversion This article contains Supplementary Data online at http://care.diabetesjournals.org/lookup/ to multiple positivity for autoAbs. In time-dependent Cox regression, younger age suppl/doi:10.2337/dc16-2228/-/DC1. P HLA-DQ2/DQ8 P ( =0.042), genotype ( = 0.009), and the development of additional F.K.G. and E.V.B. contributed equally to this autoAbs (P = 0.012) were associated with more rapid progression to diabetes. work. *A complete list of the Members of the Belgian CONCLUSIONS Diabetes Registry can be found in the Supple- In single-autoAb+ relatives, the time to multiple-autoAb positivity increases with age mentary Data online. and the absence of IAA and HLA-DQ2/DQ8 genotype. The majority of multiple- © 2017 by the American Diabetes Association. autoAb+ individuals progress to diabetes within 20 years; this occurs more rapidly Readers may use this article as long as the work in the presence of IA-2A or ZnT8A, regardless of age, HLA-DQ genotype, and number is properly cited, the use is educational and not for profit, and the work is not altered. More infor- of autoAbs. These data may help to refine the risk stratification of presymptomatic mation is available at http://www.diabetesjournals type 1 diabetes. .org/content/license. 1066 Twenty-Year Progression to Type 1 Diabetes Diabetes Care Volume 40, August 2017 Type 1 diabetes is a chronic autoimmune RESEARCH DESIGN AND METHODS clinical onset. BMI was expressed as an disease with an incidence peak around Participants SD score (BMI-SDS) by comparison with puberty (1,2). Observational studies Between March 1989 and December an age- and sex-matched cohort (15). from births in Germany, Finland, and 2015, the BDR consecutively recruited sib- Colorado have followed children at fa- lings or offspring (under 40 years of age at Analytical Methods The presence of IAA, GADA, IA-2A, and milial or HLA-DQ/DR genotype–inferred study entry) of type 1 probands with di- ZnT8A was determined by liquid-phase disease risk for the development of auto- abetes according to previously defined radiobinding assay (12), and that of HLA- antibodies (autoAbs) against insulin criteria (2). The probands are considered DQ polymorphisms was determined by (IAA), GAD65 (GADA), and IA-2 antigen representative of the Belgian population allele-specific oligonucleotide genotyping (IA-2A) and established that .90% of of patients with type 1 diabetes (2,6). Af- (16), as described previously. cDNAs for multiple-autoAb+ individuals progress to ter obtaining written informed consent the preparation of radioligands by in vitro clinical onset within 20 years from sero- from each relative or their parents, a transcription translation were gifts from conversion, with the first autoAb appear- short questionnaire with demographic, A.˚ Lernmark (when at University of Wash- ing most often before 5 years of age (3). familial, and personal information was ington, Seattle, WA) for full-length 65-kDa Reports that also included adults have, completed at each visit, and blood sam- glutamate decarboxylase, M. Christie however, indicated that an important ples were taken at study entry and, as a (King’s College School of Medicine and fraction of seroconversions to autoAb rule, yearly thereafter. Only relatives with Dentistry, London, UK) for the intracellu- positivity occurs after 10 years of age (4) two or more contacts during the fol- lar portion of IA-2, and J.C. Hutton (Barbara and that the disease can become clini- low-up period (7,029 individuals), with Davis Center for Childhood Diabetes, cally overt at any age, with development the last contact being at diagnosis in the Aurora, CO) for the dimeric hybrid ZnT8A of the disease occurring in adulthood in case of progression to diabetes, were in- construct generated by the fusion of CR the majority of patients (2,5–7). There is cluded in this study. The median intervals and CW (zinc transporter-8 carboxy- growing consensus that immune inter- between successive visits ranged be- terminal constructs carrying, respec- ventions in patients with type 1 diabetes tween 11 and 13 months for the various tively, Arg325 and Trp325). ZnT8A were should concentrate on the presymptom- groups of relatives studied. Diabetes was determined in all relatives positive for atic disease phase (8–10). Relatively non- diagnosedaccordingtotheAmerican IAA, GADA, and/or IA-2A but in only a frac- specific interventions, such as anti-CD3 Diabetes Association criteria (14). tion of participants who tested negative therapy, may have to include adults first, The study was conducted in accordance for the other three autoAbs (n = 546; to evaluate safety and efficacy, before with the guidelines in the Declaration of 8.7%), in view of the reported low preva- enrolling children (10). Consequently, Helsinki, as revised in 2013 (accessed lence of solitary ZnT8A positivity (4,12,17). there is a need to compare criteria for on 18 May 2017; https://www.wma disease staging (11) in adults and children .net/policies-post/wma-declaration-of- Statistical Analysis who are at risk. helsinki-ethical-principles-for-medical- Statistical differences between groups Since 1989 the Belgian Diabetes Regis- research-involving-human-subjects/), and were assessed by x2 test, with Yates cor- try (BDR) has recruited first-degree rela- approved by the ethics committees of the rection or Fisher exact test for categorical tives who are ,40 years of age and BDR and the participating university hos- variables and Mann-Whitney U test for monitored their immunogenetic char- pitals. Random blood samples were col- continuous data. Kaplan-Meier analysis acteristics (IAA, GADA,IA-2A, zinc trans- lected for sera and buffy coats, and was used to estimate diabetes-free sur- porter 8 autoAbs [ZnT8A], and HLA-DQ aliquots were stored at 280°C until ana- vival. The survival curves were compared genotype) in relation to clinical outcome lyzed for diabetes-associated autoAbs using the log-rank test. Follow-up for without preselection according to initial and HLA-DQ genotype, respectively, as diabetes-free survival started at the time autoAb status or genotype (10). We pre- described previously (12). All relatives of the first autoAb+ sample and ended viously reported (12,13) that the pres- were followed regardless of their autoAb at the last contact with the relative or at ence of IA-2A or ZnT8A plus at least one status and HLA-DQ genotype. Relatives clinical onset, whichever came first. other diabetes autoAb type conferred a were not prescreened for islet cell cyto- When assessing multiple-autoAb positiv- high and age-independent risk of progres- plasmic autoAbs (ICA), nor were ICA re- ity as the end point, follow-up ended at sion to diabetes within 5–10 years in first- sults analyzed in the current study. thetimeofthefirst multiple-autoAb+ degree relatives. Here, we investigated AutoAb positivity was defined as being sample. The persistence of multiple- the influence of autoAb profile (number persistent if the next sample was also pos- autoAb positivity was defined as being still and type) and age at first autoAb positiv- itive for at least one autoAb regardless of positive for at least two autoAbs regard- ity on progression to type 1 diabetes in an the type. During follow-up, development less of the type at the next sampling time. extended group of siblings and offspring, of diabetes was ascertained through re- The following age strata were considered: who were followed over a longer obser- peated contacts of the BDR with Belgian 0–9, 10–19, and 20–39 years of age.